Urinary Leukotriene E4 to Determine Aspirin Intolerance in Asthma: A Systematic Review and Meta-Analysis

Background Urinary leukotriene E4 (ULTE4) may be a biomarker that distinguishes aspirin-intolerant asthma from other asthma subtypes. Objective To estimate the diagnostic testing accuracy of ULTE4 as a marker of aspirin intolerance in patients with asthma using previously published studies. Methods We identified relevant clinical studies from a systematic review of English and non-English articles using MEDLINE, EMBASE, and CENTRAL (inception to February 10, 2015). Articles were screened at the abstract and full-text level by 2 independent reviewers. We included previously published studies that analyzed ULTE4 in human subjects with asthma characterized as having or not having aspirin intolerance on the basis of a specified definition: convincing history of aspirin intolerance, positive aspirin challenge, or both as the criterion standard. Individual-level data points from all included studies were obtained and analyzed. Results The search strategy identified 867 potential articles, of which 86 were reviewed at the full-text level and 10 met criteria for inclusion. The sensitivity, specificity, positive predictive value, and negative predictive values of ULTE4 to determine aspirin intolerance in subjects with asthma were 0.55, 0.82, 0.75, and 0.66 (Amersham-enzyme immunoassay); 0.76, 0.77, 0.70, and 0.78 (Cayman-enzyme immunoassay); 0.70, 0.81, 0.86, and 0.79 (mass spectrometry); and 0.81,0.79, 0.65, and 0.88 (radioimmunoassay) at optimal thresholds of 192, 510, 167 to 173, and 66 to 69 pg/mg Cr, respectively. The diagnostic odds ratio for each methodology was 6.0, 11.9, 10.5, and 19.1, respectively. Conclusions ULTE4 is a marker for aspirin-intolerant asthma and could potentially be used as a clinical test to identify the risk of aspirin intolerance in subjects with asthma.